ericfx1984
Solar Enthusiast
- Joined
- Oct 10, 2021
- Messages
- 724
So I did my first test last night... New build, Eve cells 230ah, 4s, JBD 200a BMS, I built two of these batteries
I hooked up a msw 750w inverter to a heater on low, 671w on the AC side, 853w on the DC side
The first battery pulled full capacity no issues... However I was not able to pull down to low voltage disconnect only about 2.7v per cell (recovered to 3.02v)... At this point the inverter was not happy as we were so close to its maximum wattage anyway.. the inverter shut down due to heat
However the battery pulled more than full capacity and was at full capacity before heading 12 volts
And I went to test the other battery I noticed that the voltage had dropped and was setting around 3.35v per cell. This is confusing because the only thing that was actually hooked up was the BMS
I did test it for about 10 seconds the night before and it wasn't registering any amperage so I checked all my connections everything seemed fine but here we are
Anyway I'm not sure if it's worth it to do a capacity test now or if I should recharge the battery but I'm confused as to why it would self discharge like that? BMS shouldn't really draw anything right?
So I guess my question is should I be concerned about the discharge that I'm seeing on one battery? Or should I just capacity test it and see what it does?
And my other question is should I be concerned that I wasn't able to fully complete the capacity test on the first battery or should I just leave well enough alone since it did test above rated capacity and I did not have to draw the battery fully down to get there?
I hooked up a msw 750w inverter to a heater on low, 671w on the AC side, 853w on the DC side
The first battery pulled full capacity no issues... However I was not able to pull down to low voltage disconnect only about 2.7v per cell (recovered to 3.02v)... At this point the inverter was not happy as we were so close to its maximum wattage anyway.. the inverter shut down due to heat
However the battery pulled more than full capacity and was at full capacity before heading 12 volts
And I went to test the other battery I noticed that the voltage had dropped and was setting around 3.35v per cell. This is confusing because the only thing that was actually hooked up was the BMS
I did test it for about 10 seconds the night before and it wasn't registering any amperage so I checked all my connections everything seemed fine but here we are
Anyway I'm not sure if it's worth it to do a capacity test now or if I should recharge the battery but I'm confused as to why it would self discharge like that? BMS shouldn't really draw anything right?
So I guess my question is should I be concerned about the discharge that I'm seeing on one battery? Or should I just capacity test it and see what it does?
And my other question is should I be concerned that I wasn't able to fully complete the capacity test on the first battery or should I just leave well enough alone since it did test above rated capacity and I did not have to draw the battery fully down to get there?